Updated Slovenian translation
Improve debugging for drag & drop in media/effects library and clip properties
clipproperties: Prevent drag and drop "ghosts" from the effects library

Ensure that dragging and dropping an effect triggers the drag_end signal;
using the "DROP" (or "ALL") flag for default DragDest allows us to correctly
signal the end of the drag and drop without calling drag_finish() ourselves.

Fixes bug #695894